摘要电导率传感器在当今人类的日常生产生活中随处可见，在现如今水污染非常严重的大环境下，对水质的监测就成了当务之急，需要一种简单可靠的电导率传感器，于是电导率传感器得到了大力的发展。电极式传感器中四电极电导率传感器因为性能优秀而被日广泛使用。由于电极式传感器在测量过程中存在着极化作用，会让测量结果不精确，为了避免这个问题，四电极电导率传感器采用了把电压和电流的电极分开的方式。但是除了极化会对测量结果产生影响，温度也会对它产生影响，所以我在此次设计中还额外增加了温度补偿模块，最大化的减少测量误差。39756
 此次设计的流程是这样的：先把电导池中得到的敏感值也就是模拟量进行放大、滤波，在再对其进行温度补偿，再用单片机对它A/D转换，再用显示模块输出最后结果。经过上述几个步骤，就能比较精确的得到被测液体的电导率了。
毕业论文关键词：水质监测 四电极 极化效应 温度补偿
 Abstract
Conductivity sensor widely used in our production and life, and now the water pollution is very serious, on the water quality monitoring is the task of top priority, need a simple and reliable conductivity sensor, so the electrode sensor has been vigorously developing. In the electrode type sensor four electrode conductivity sensor come to the fore. Compared with the early two electrode conductivity sensor, the advantages are obvious and the measurement results are also many, developed countries have been widely used four electrode conductivity sensor.
Due to the electrode sensor in the measurement process is polarization effect, will make the measurement result is not accurate, in order to avoid this problem, four electrode conductivity sensor the voltage and current electrodes separated scheme. In addition to the impact of the polarization of the measurement results, the temperature will have an impact, so I added the design of the temperature compensation module, the maximum reduction of the measurement error.
The design of the process is this: first the conductance pool to get the amount of simulation amplification, filtering. And then detect its peak, then the temperature of its compensation, and then microcontroller A/D to it conversion, and then display the final results of the module output. After the above steps, we can get the accurate results of the measurement..
Key words:  water quality monitoring  Four electrode
Electrical conductivity  Sensor
  目  录
摘  要    I
Abstract    II
1 绪  论    1
1.1 课题的研究背景    1
1.2 电导率传感器未来发展趋势    2
1.2.1 电导率测量方法与温度补偿方法    2
1.2.2 四电极电导率传感器简述    3
1.2.3 国内外概况及应用    3
1.3 课题需要完成的任务    4
1.3.1 总体思路    4
1.3.2 传感器探头选择    4
1.3.3 电导池的设计与制作    4
1.3.4 温度补偿    5
2 四电极电导率传感器设计的理论依据    7
2.1 溶液的电导和电导率    7
2.2 电导率的测量原理及几种常用方法介绍    8
2.3 影响电导率测量的几个因素    8
3 硬件设计    12
3.1 整体设计方案    12
3.2 结构设计    12
3.3 部分硬件设计    13
3.3.1 单片机的选型    13
3.3.2 电源模块    14
3.3.3 处理电路    15
3.3.4 温度补偿电路    17 四电极电导率传感器的设计+电路图:http://www.youerw.com/zidonghua/lunwen_40417.html